The Spherical Neutral Detector (SND) is intended for study of electron–positron annihilation at the VEPP-2000 e+e− collider (BINP, Novosibirsk) in the center-of-mass energy region below 2GeV. The main part of the detector is a three-layer electromagnetic calorimeter based on NaI(Tl) crystals. The physics program of the SND experiment includes a high statistics study of neutron–antineutron production near threshold, for which time measurements in the calorimeter are required. In this paper we describe new shaping and digitizing calorimeter electronics, which allow to reach a time resolution of about 1ns for 100MeV signal and an amplitude resolution of about 250keV.